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<h1 class="title">graph.cpp 示例文件</h1>
<span class="subtitle">scenegraph/graph/graph.cpp</span>
<!-- $$$scenegraph/graph/graph.cpp-description -->
<div class="descr"> <a name="details"></a>
<pre class="cpp">

  <span class="comment">/****************************************************************************
  **
  ** Copyright (C) 2017 The Qt Company Ltd.
  ** Contact: https://www.qt.io/licensing/
  **
  ** This file is part of the examples of the Qt Toolkit.
  **
  ** $QT_BEGIN_LICENSE:BSD$
  ** Commercial License Usage
  ** Licensees holding valid commercial Qt licenses may use this file in
  ** accordance with the commercial license agreement provided with the
  ** Software or, alternatively, in accordance with the terms contained in
  ** a written agreement between you and The Qt Company. For licensing terms
  ** and conditions see https://www.qt.io/terms-conditions. For further
  ** information use the contact form at https://www.qt.io/contact-us.
  **
  ** BSD License Usage
  ** Alternatively, you may use this file under the terms of the BSD license
  ** as follows:
  **
  ** &quot;Redistribution and use in source and binary forms, with or without
  ** modification, are permitted provided that the following conditions are
  ** met:
  **   * Redistributions of source code must retain the above copyright
  **     notice, this list of conditions and the following disclaimer.
  **   * Redistributions in binary form must reproduce the above copyright
  **     notice, this list of conditions and the following disclaimer in
  **     the documentation and/or other materials provided with the
  **     distribution.
  **   * Neither the name of The Qt Company Ltd nor the names of its
  **     contributors may be used to endorse or promote products derived
  **     from this software without specific prior written permission.
  **
  **
  ** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  ** &quot;AS IS&quot; AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  ** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  ** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  ** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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  ** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  ** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  ** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.&quot;
  **
  ** $QT_END_LICENSE$
  **
  ****************************************************************************/</span>

  <span class="preprocessor">#include &quot;graph.h&quot;</span>

  <span class="preprocessor">#include &quot;noisynode.h&quot;</span>
  <span class="preprocessor">#include &quot;gridnode.h&quot;</span>
  <span class="preprocessor">#include &quot;linenode.h&quot;</span>

  Graph<span class="operator">::</span>Graph()
      : m_samplesChanged(<span class="keyword">false</span>)
      <span class="operator">,</span> m_geometryChanged(<span class="keyword">false</span>)
  {
      setFlag(ItemHasContents<span class="operator">,</span> <span class="keyword">true</span>);
  }

  <span class="type">void</span> Graph<span class="operator">::</span>appendSample(<span class="type"><a href="../qtcore/qtglobal.html#qreal-typedef">qreal</a></span> value)
  {
      m_samples <span class="operator">&lt;</span><span class="operator">&lt;</span> value;
      m_samplesChanged <span class="operator">=</span> <span class="keyword">true</span>;
      update();
  }

  <span class="type">void</span> Graph<span class="operator">::</span>removeFirstSample()
  {
      m_samples<span class="operator">.</span>removeFirst();
      m_samplesChanged <span class="operator">=</span> <span class="keyword">true</span>;
      update();
  }

  <span class="type">void</span> Graph<span class="operator">::</span>geometryChanged(<span class="keyword">const</span> <span class="type"><a href="../qtcore/qrectf.html">QRectF</a></span> <span class="operator">&amp;</span>newGeometry<span class="operator">,</span> <span class="keyword">const</span> <span class="type"><a href="../qtcore/qrectf.html">QRectF</a></span> <span class="operator">&amp;</span>oldGeometry)
  {
      m_geometryChanged <span class="operator">=</span> <span class="keyword">true</span>;
      update();
      <span class="type"><a href="qquickitem.html">QQuickItem</a></span><span class="operator">::</span>geometryChanged(newGeometry<span class="operator">,</span> oldGeometry);
  }

  <span class="keyword">class</span> GraphNode : <span class="keyword">public</span> <span class="type"><a href="qsgnode.html">QSGNode</a></span>
  {
  <span class="keyword">public</span>:
      NoisyNode <span class="operator">*</span>background;
      GridNode <span class="operator">*</span>grid;
      LineNode <span class="operator">*</span>line;
      LineNode <span class="operator">*</span>shadow;
  };

  <span class="type"><a href="qsgnode.html">QSGNode</a></span> <span class="operator">*</span>Graph<span class="operator">::</span>updatePaintNode(<span class="type"><a href="qsgnode.html">QSGNode</a></span> <span class="operator">*</span>oldNode<span class="operator">,</span> UpdatePaintNodeData <span class="operator">*</span>)
  {
      GraphNode <span class="operator">*</span>n<span class="operator">=</span> <span class="keyword">static_cast</span><span class="operator">&lt;</span>GraphNode <span class="operator">*</span><span class="operator">&gt;</span>(oldNode);

      <span class="type"><a href="../qtcore/qrectf.html">QRectF</a></span> rect <span class="operator">=</span> boundingRect();

      <span class="keyword">if</span> (rect<span class="operator">.</span>isEmpty()) {
          <span class="keyword">delete</span> n;
          <span class="keyword">return</span> nullptr;
      }

      <span class="keyword">if</span> (<span class="operator">!</span>n) {
          n <span class="operator">=</span> <span class="keyword">new</span> GraphNode();

          n<span class="operator">-</span><span class="operator">&gt;</span>background <span class="operator">=</span> <span class="keyword">new</span> NoisyNode(window());
          n<span class="operator">-</span><span class="operator">&gt;</span>grid <span class="operator">=</span> <span class="keyword">new</span> GridNode();
          n<span class="operator">-</span><span class="operator">&gt;</span>line <span class="operator">=</span> <span class="keyword">new</span> LineNode(<span class="number">10</span><span class="operator">,</span> <span class="number">0.5</span><span class="operator">,</span> <span class="type"><a href="../qtgui/qcolor.html">QColor</a></span>(<span class="string">&quot;steelblue&quot;</span>));
          n<span class="operator">-</span><span class="operator">&gt;</span>shadow <span class="operator">=</span> <span class="keyword">new</span> LineNode(<span class="number">20</span><span class="operator">,</span> <span class="number">0.2f</span><span class="operator">,</span> <span class="type"><a href="../qtgui/qcolor.html">QColor</a></span><span class="operator">::</span>fromRgbF(<span class="number">0.2</span><span class="operator">,</span> <span class="number">0.2</span><span class="operator">,</span> <span class="number">0.2</span><span class="operator">,</span> <span class="number">0.4</span>));

          n<span class="operator">-</span><span class="operator">&gt;</span>appendChildNode(n<span class="operator">-</span><span class="operator">&gt;</span>background);
          n<span class="operator">-</span><span class="operator">&gt;</span>appendChildNode(n<span class="operator">-</span><span class="operator">&gt;</span>grid);
          n<span class="operator">-</span><span class="operator">&gt;</span>appendChildNode(n<span class="operator">-</span><span class="operator">&gt;</span>shadow);
          n<span class="operator">-</span><span class="operator">&gt;</span>appendChildNode(n<span class="operator">-</span><span class="operator">&gt;</span>line);
      }

      <span class="keyword">if</span> (m_geometryChanged) {
          n<span class="operator">-</span><span class="operator">&gt;</span>background<span class="operator">-</span><span class="operator">&gt;</span>setRect(rect);
          n<span class="operator">-</span><span class="operator">&gt;</span>grid<span class="operator">-</span><span class="operator">&gt;</span>setRect(rect);
      }

      <span class="keyword">if</span> (m_geometryChanged <span class="operator">|</span><span class="operator">|</span> m_samplesChanged) {
          n<span class="operator">-</span><span class="operator">&gt;</span>line<span class="operator">-</span><span class="operator">&gt;</span>updateGeometry(rect<span class="operator">,</span> m_samples);
          <span class="comment">// We don't need to calculate the geometry twice, so just steal it from the other one...</span>
          n<span class="operator">-</span><span class="operator">&gt;</span>shadow<span class="operator">-</span><span class="operator">&gt;</span>setGeometry(n<span class="operator">-</span><span class="operator">&gt;</span>line<span class="operator">-</span><span class="operator">&gt;</span>geometry());
      }

      m_geometryChanged <span class="operator">=</span> <span class="keyword">false</span>;
      m_samplesChanged <span class="operator">=</span> <span class="keyword">false</span>;

      <span class="keyword">return</span> n;
  }

</pre>
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<!-- @@@scenegraph/graph/graph.cpp -->
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